This invention relates to a fixing device for an electronic duplicator machine and, more particularly, to a fixing device for an electronic duplicator machine which is equipped with a heat generating roller for heating non-fixed toner transferred onto a copying paper and fixing the toner onto the same.
There have recently been put to practical use a number of fixing devices, for the reasons that they have as one of their merits the capability of obtaining a stable fixed image, each of which comprises a rotary heat generating roller and a copying paper supporting means which is provided to oppose the roller and which supports the copying paper, to which non-fixed toner is to be attached, so as to permit the paper to contact the roller, whereby the non-fixed toner is heated and fixed onto the copying paper.
Conventionally, in the above-mentioned type of fixing devices such a heat generating roller (10) as shown in FIG. 1 is employed. The roller (10) comprises a roller body (14) which is rotatably supported by means of bearings or journals (12) and a tubular infrared ray heater (16) which is provided in alignment with the central axis of the roller body (14), whereby a coating (20) of, for example, silicon rubber is applied onto the outer circumferential surface of a core (18) the roller body (14) being heated by the generation of heat from the tubular infrared ray heater (16), up to a predetermined temperature.
Since, as stated above, the fixing device equipped with the heat generating roller (10) uses the tubular infrared ray heater (16) at the central axis of the roller body and thereby heats the coating (20) up to a fixable temperature, the time required until the arrival at such fixable temperature, i.e., the warming up time, is about 3 to 5 minutes as indicated by broken line (A) in FIG. 2. This warming up time is very long as compared with that required for another heat generating means (radiant means) which is about 1 to 3 minutes as indicated by a two-dot dash line (B) also in FIG. 2. This does not only irritate the operator but also results in a large loss of heat thereby causing an increase in the power consumption.